This window portrays a stone-mason in a knee-length yellow tunic and blue hose. The inscription names William Campiun and gives a date which looks like 1313. It is one of the earliest windows in England showing an artisan at his work. It was cleaned and re-leaded in 1976-7. With its original lead it was lent to the Age of Chivalry exhibition of 1987-8, and is discussed in the catalogue. The old lead hangs in a case near the window.

The sedilia in the chancel is fourteenth-century and is probably William Campiun's work.

There is an excellent picture of the Campiun window on the cover of the Shire Archaeology handbook Medieval Masons by Malcolm Hislop, published 2000. The cover caption records the fact that it is a "fourteenth-century stained glass panel from St Mary Magdalene, depicting a mason, William Campiun, wielding his mason's axe." Although there is no further mention of William, the book is nevertheless informative and interesting, providing a practical guide to pursuing the study of medieval masoncraft.